Process of producing n-monosubstituted sulfenamides



Patented Jan. 8, 1952 PROCESS OF PRODUCING N'-'MONO- SUBSTITUTED.SULFENAMIDES Glen Alliger, Akron, Ohio, assignor to The Firestone Tire &Rubber Co corporation of Ohio mpany, Akron, Ohio, at.

No Drawing. Application December 14, 1949, Serial No. 133,015

41 Claims.

This invention relates to the production of N-mono-substitutedsulfenamides. More particularly, it relates to the production ofsulienamides in large particles which are more easily filtered than thesmaller sized particles produced heretofore.

In my prior application Serial No. 695,545 filed September 7, 1946 whichhas now matured into Patent No. 2,495,085 there is described theproduction of (1) N-isopropyl benzothiazyl sulfenamide fromN-mono-chloro-isopropylamine and sodium 2 mercaptobenzothiazole, (2)N-cyclohexyl-2-mercaptobenzothiazyl sulfenamide fromN-mono-chloro-cyclohexylamine and 2-mercaptobenzothiazole, and (3)N-cyclohexyl-N',N'-diethylthiocarbamyl sulienamide fromN-chlorocyclohexylamine and sodium diethyl-dithiocarbamate. The reactionis carried out at a low temperature for example, a temperature belowabout C., and for commercial operations within the range of about 10 C.to about 20 or 30 C. Also, the solution concentrations are kept so highthat a minimal amount of the N-mono-chloro primary amine is in solution.For that purpose there may be used a 1.5 .to 3.5 molar concentration ofmercaptide and a 1.5 to 3.0 molar concentration of hypochlorite, whichon mixing yield a solution which is at least 0.75 molar with respect toeach of the reactants or reaction products. The sulfenamides areobtained in fine particle size according to the procedures theredescribed. According to this invention, sulfenamides produced by thatprocess or other processes involve the reaction of a mercaptide, anamine and an oxidizing agent. Oxidizing agents which may be used arewell known in the art and include chlorine, bromine, iodine,hypochlorous acid, hypobrom'ous acid, hypoiodous acid, the alkali metaland alkaline earth metal salts of those acids, hydrogen peroxide, sodiumpersulfate, potassium dichromate, potassium ferricyanide, etc.

According to this invention the reaction product is recovered in theform of more easily filterable aggregates by filtering from a two-phaseliquid medium, in one phase of which is an organic solvent for theproduct. The solvent must be inert with respect to the reactants, namelythe amine, the oxidizing agent and the mercaptide, and "also with"respect to the product of the reaction. The solvent is relatively butpletely insoluble in water and is used in such an amount that there ispresent during the formation or. filtration of the product a secondliquid phase, although the amount of solvent employed is not sufficientto dissolve an appreciable. amount of the product. The organic solventused must be at least one part soluble in parts of water at the reactiontemperature and must dissolve the reaction product to the extent of fiveto thirty parts per 100 parts of solvent at the reaction temperature.Organic solvents such as diethyl ether, methylethyl ketone, n-butylalcohol, isobutyl alcohol, sec-butyl alcohol, benzyl alcohol, ethylacetate, etc. may be used. Petroleum ether is not sutficiently solublein water. Methyl alcohol and ethyl alcohol, being completely miscible inwater, are not. satisfactory. The solvent is preferably added to thereaction mixture before precipitation of the sulfenamide, but may beadded to the slurry of the freshly precipitated sulfenamide in water,with agitation to form agglomerates which are easily filterable.

The process of my aforesaid patent involves, as a first'step, theproduction of a N-mono-chloro primary amine from a primary amine, ofwhich a number are mentioned in the patent. The process of thisinvention is not limited to such a two-step operation, and other aminesthan primary amines may be used, all as is evident from the prior art.The primary amines which may be used include methylamine, ethylamine,the propylamines, the butylamines, cyclohexylamine,benzylamine,'ally1amine, ethylenediamine, hexahydrobenzylamine,furfurylamine, thenylamine, etc. There are various U. S. patents thatsuggest the use of secondary amines including the usual aliphatic aminessuch as dimethylamine, diethylamine, dicyclohexylamine, dibenzylamine,etc., and cyclic compounds such as piperidine, morpholine, etc. All suchnon-aromatic amines may be employed.

Alkali metal and alkaline earth metal mercaptides which may be used inthe process include, for example, those produced from the followingmercaptans: thiophenol, thio-beta-naphthol, 2-mercaptothiazoline,2-mercapto 4,5-dihydroglyoxaline, Z-mercaptobenzoxazole, Z-mercapto4,5-dimethylthiazole, 2-mercapto-4-ethylthiazole,2-mercaptobenzothiazole, 2-mercaptomethnot com- .ylbenzothiazole, 2mereaptochlorobenzothiazole, and N,N-diethyldithiocarbamic acid. Thesodi- 4 ter, although this property could only be evaluatedqualitatively as poor, fair, or excellent in the above record of theresults obtained.

mide under varying conditions tabulated below: 7

TABLE The solvent need not be added before precipitation but may beadded to the slurry of the precipitate. For example, by adding about 10per cent by volume of diethyl ether, n-butyl alcohol, ethyl acetate,etc. to the reaction mixture consisting of a slurry of N-isopropylbenzothiazyl sulfenamide suspended in an aqueous mixture of an amine,caustic soda and sodium chloride, and slowly agitating the mixture, theparticle size of the N-isopropyl benzothlazyl sulfenamide was increasedso that it readily fil- Eflect of ether on particle size ofN-isop'ropylz-benzothiazyl sulfenamide Run No 1 2 3 4 i s e 7 AdditionTime:

NaOClSolutiom. hr 34hr. Mercaptide Soln- 1% hr Ahr. wi l no. 0 er O NaOCl 2.77. 2.77. Mercaptide 3.0- 3.0. Teiip. of Reaction, 0-5. 0-5. P61cent Yield 88 s4. Ether per half mole... 80 20. Ether per cent by 21.25.3.

volume. I Filterability... Poor Poor. Excellent- Excellent--.Excellent... Excellent... Fa1r. Relative ParticleSize. Fine Fine CoarseCoarse Coarse Coarse Medium Coarse.

In carrying out each of the seven reactions. 1.25 moles ofisopropylamine, 1.15 moles of sodium hypochlorite and 1.00 mole ofsodium salt of mercaptobenzothiazole (obtained from commercialmercaptobenzothiazole analyzing 94. per cent pure) were used. In .Runs 1and 2 no ether was used. In Run 3 the reaction mixture, on

completion of the reaction, was stirred .overnight while comi-ng to roomtemperature. In Run 4 the reaction mixture was filtered immediatelyafter completion of the reaction." It will be observed that in bothcases a good yield was obtained and the particles were sufficientlylarge to be readily'filtered. The yields were calculated on themercaptobenzothiazole employed. A slight excess of primary amine 10 toper cent, for example) was used to prevent the formation ofN-dichloroamine.

The filterability rating was based 'on a microscopic examination of thewet product. In each run the reaction mixture was diluted to 1.5 litersafter addition of the sodium mercaptide to bring the ether into solutionin the aqueous phase.

The mixture was then filtered and washed three or four times byreslurrying in 1.5 liters of ,distilled water and filtering. .Washingwas continued until the filtrate was neutral to litmus and gave no testfor chloride ion. After suck-e ing the solid as dry as possible on aBuchner funnel, it was dried in layers one-quarter inch in depth in anoven at C. Photornicrographs obtained with the use of ether was clearlybettered and a clear filtrate was obtained.

It is not necessar o i st prepa a 9 .11pm mine and hen rea ha w th a mree iidci the eactants may he add d n an order shown in h p ior art. T eimprovement ha n tliies to do with the ch m cal e c on, but ith the recv ry of the s lfe am dc hich i foa d..-

If he s lv nt i add d before comple ion .0? the chemical rea t on as nthe i-e ecine am les, t a no p t table ef ect on the cou e 0; thereaction.

What I claim is:

1. In the proce s of p oducin ul ncm dc om a mercapt de a penromaticamin and an oxidizin ag nt. aq eo s se u ics th ink movement whi h. nsts fi rin thcreac tio produ t i rcm an aqueou reaction mix ure in thepres n e of a secon liqu d phase contains an reams s vent wh ch i net.11? pletely miscibl with wate is inert w th respect to the reactantsand the product of the re p-ti *1. is soluble in water to the ex n of ale st Jane part of lv n in 1.60 par s 0. Water at the re actiontemperature, and dissolves five to thirty parts of the sui c a dc an?hundred par of sol nt at th r action tempe atu t sol.- v being pre entsu h smal am unt hat it does not dissolve any sub nt al amou t (I thesulfenamide.

2. In the process o pr ducin a ul en misic from a m r an de; a cn a cmatc amin and amide in one hundred parts of solvent .at-the reactiontemperature, the solvent being present in such small amount that it doesnot dissolve any substantial amount of the sulfenaxnide, and filteringoff the reaction product.

3. In the process of producing a sulfenamide from a mercaptide, anon-aromatic amine and an oxidizing agent in aqueous solution, theimprovement which consists in filtering the reaction product from anaqueous reaction mixture in the presence of ether, the amount of etherbeing insufiicient to dissolve any substantial amount of thesulfenamide.

4. In the process of producing a sulfenamide from a mercaptide, anon-aromatic amine and an oxidizing agent in aqueous solution, the im-15 5,

provement which consists in completing the reaction in aqueous solutionin the presence 01' ether, the amount of ether being insuflicient todissolve any substantial amount of the sulfenamide, and filtering offthe reaction product from the ether-containing mixture.

GLEN ALLIGER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Alliger Jan. 17, 1950 Number

1. IN THE PROCESS OF PRODUCING A SULFENAMIDE FROM A MERCAPTIDE, A NON-AROMATIC AMINE AND AN OXIDIZING AGENT IN AQUEOUS SOLUTUON, THE IMPROVEMENT WHICH CONSISTS IN FILTERING THE REACTION PRODUCT FROM AN AQUEOUS REACTION MIXTURE IN THE PRESENCE OF A SECOND LIQUID PHASE WHICH CONTAINS AN ORGANIC SOLVENT WHICH IS NOT COMPLETELY MISCIBLE WITH WATER, IS INERT WITH RESPECT TO THE REACTANTS AND THE PRODUCT OF THE REACTION, IS SOLUBLE IN WATER TO THE EXTENT OF AT LEAST ONE PART OF SOLVENT IN 100 PARTS OF WATER AT THE REACTION TEMPERATURE, AND DISSOLVES FIVE TO THIRTY PARTS OF THE SULFENAMIDE IN ONE HUNDRED PARTS OF SOLVENT AT THE REACTION TEMPERATURE, THE SOLVENT BEING PRESENT IN SUCH SMALL AMOUNT THAT IT DOES NOT DISSOLVE ANY SUBSTANTIAL AMOUNT OF THE SULFENAMIDE. 